A structured 40-point commissioning verification confirms an air handling unit delivers the airflow, pressure, temperature, and filtration the design intended before the system is handed over.
What Commissioning Confirms
An AHU may be mechanically complete yet still fail the building because a damper is wired backwards, a coil is air-bound, or the fan is running at the wrong speed. Commissioning closes that gap between "installed" and "performing." The 40 points span mechanical, electrical, controls, and air-side performance, and each is documented with a measured value rather than a tick box, so the record shows what the unit actually does, not what someone hoped it would.
The payoff is measurable: a commissioned unit typically recovers 5โ15% of wasted energy and avoids the finger-pointing that follows a vague "it doesn't work" complaint after occupation. More importantly, the building opens with proof that the design intent was met, which protects both the operator and the design team if a dispute arises later.
Commissioning is a sequence, not a single visit. Pre-commissioning confirms the unit is complete and safe to energise: filters fitted, coils flushed, dampers free, guards in place. Static checks follow with the fan locked off, covering insulation resistance, rotation, and sensor calibration. Dynamic checks then run the unit through every mode, and seasonal checks revisit heating or cooling performance when the weather finally allows a real load. Skipping the seasonal visit is the most common shortcut, and it is why a unit signed off in October can fail its first hot week. On a medium unit the whole exercise is typically two to four days of site time, and it needs the controls contractor present, not only the mechanical installer.
The 40-Point Verification by Group
The points are grouped so nothing falls between trades. Air side covers flow balance and static; water side covers coil and valve; controls cover sequences and interlocks; safety covers smoke, freeze, and access. Each group is owned by the relevant trade but signed off on one consolidated sheet, which is what makes the process auditable rather than a stack of disconnected reports.
| Group | Points | What is checked |
|---|---|---|
| Air side | 12 | Flow, static, filter drop, discharge air temp |
| Water side | 8 | Coil, valve authority, pump Delta-T |
| Controls | 10 | Sequences, sensors, alarms, schedules |
| Electrical | 6 | Motors, starters, phase, isolation |
| Safety | 4 | Smoke interlock, freeze stat, access |
| Total | 40 | All groups, each signed with a measured value |
| Site time | 2–4 days | Medium unit, all four commissioning stages |
Taken together the groups total 40 checks. Each is signed off with a measured number, so a later dispute about "was the filter pressure drop verified" is answered by the record, not memory, and the O&M team inherits a baseline against which future degradation is judged.
Each measured value needs a stated method, otherwise two commissioning agents produce two different answers. Airflow is normally taken by pitot traverse in a straight duct run or by a calibrated flow hood at the terminals, with the traverse plane several duct diameters downstream of any disturbance. Static pressure is read across the fan and across each filter bank at design flow, and the clean filter drop becomes the baseline for the change-out setpoint, often set at two to two-and-a-half times the clean value. Temperatures are logged on air and water sides simultaneously so a coil is judged on its actual approach rather than on a single leaving-air reading. Instrument calibration certificates belong in the file with the results.
Commissioning Checklist
- Balance airflow: Confirm supply, return, and exhaust within 10% of design before control tuning.
- Verify sequences: Minimum outdoor air, economizer, and night setback all operate as drawn.
- Record pressures: Capture filter and coil pressure drops at design flow for the O&M file.
- Test interlocks: Smoke and freeze stats actually stop or modulate the unit when triggered.
- Baseline energy: Log the commissioned kW at design condition for future comparison.
- Book the seasonal visit: Re-verify heating or cooling capacity under real load, not only at handover weather.
- State the method: Record how each value was measured and with which calibrated instrument.
Why a Fixed Checklist Helps
A consistent 40-point method means two different sites get the same rigor and the O&M record is comparable. Keruite supports commissioning by supplying the declared coil, fan, and filter data the verifier needs to judge pass or fail against design intent, so the commissioning agent is not reconstructing performance from a bare nameplate.
Commissioning only works when the manufacturer's declared data is good enough to test against, because the exercise compares measured against declared throughout. Coil and fan data traced to an in-house performance laboratory, inside a plant of 80,000 m² with more than 30 years of unit fabrication behind it, gives the verifying engineer a defensible reference instead of a rounded catalogue figure. ISO 9001:2015 and CCC certification cover the production and electrical side of the same unit, and because equipment goes to more than 50 countries the submittal set is prepared to suit both ASHRAE-based and European commissioning practice, which differ in how tolerances are expressed.
Our engineers respond to selection enquiries within 24 hours, including AHU performance data and submittal inputs for commissioning teams.